Bicycle crank system

ABSTRACT

A bicycle crank assembly includes a spindle connection arrangement for connecting a first and second crank arm to a bicycle frame. The first crank arm includes a first portion of the spindle and the second crank arm includes a second portion of the spindle. The first and second spindle portions are connected to one another using two spaced apart bearing surfaces that provide a durable yet easily disassemblable spindle. The crank assembly also includes a removable chain ring and a chain ring adjuster for adjusting the position of the chain ring along the rotational axis of the spindle in order to allow the chain ring to be properly aligned with other components of the bicycle. In one embodiment, the assembly includes variable length crank arms that increase the ground clearance of the crank assembly and improve the leverage provided by the crank assembly during the downward stroke of the crank assembly. In another embodiment, the crank assembly includes a pedal connection arrangement for attaching a bicycle shoe to a pedal.

This is a application of copending prior application Ser. No.09/146,766, filed on Sep. 3,1998, now U.S. Pat. No. 6,199,449 thedisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to bicycle components and morespecifically to bicycle crank assemblies.

Presently, bicycles have grown to a high level of popularity and manybicycles are highly specialized for certain applications. Thesespecialized applications impose extraordinary requirements on variousbicycle components. Despite these extraordinary requirements, many ofthe basic bicycle components have remained relatively unchanged forquite some time. For occasional riders, bicycles in their present formmay be sufficient. However, specialty bicycles such as mountain bikes,racing bikes, daily commute bikes, and other specialized bikes have manycomponents that could be significantly improved. One such component isthe bicycle crank assembly.

Current crank assemblies are made up of a spindle that is mounted withina bottom bracket of a bicycle frame for rotation about a crank assemblyrotational axis. Right and left crank arms are attached to the spindleand right and left pedals are attached to the ends of the right and leftcrank arms. The crank arms and spindle are often subjected tosubstantial stresses. Often times the rider has minimal time to react tochanging trail or road conditions such as rough terrain or potholes.These jarring trail and road conditions place a heavy burden upon themechanical integrity of the crank assembly.

The pedals, crank arms, and spindle have the severe task of carrying themajority of the rider's weight, the impact loads caused by roughterrain, as well as transforming the riders leg motions into the torquethat propels the rider and the bicycle. Therefore, the crank assembly issubjected to a significant amount of torque. The continuous crankingmotion, combined with the high degree of torque, over an extended periodof time, causes wear and may eventually lead to the failure of the crankarm and/or the point where the crank arm connects to the spindle.

The most widely accepted crank arm/spindle connection system currentlyavailable is a system that utilizes a right and left crank arm, usuallymade of an aluminum alloy, and a hardened steel or titanium spindle. Thespindle has four flats machined at a slight angle on each end of thespindle creating a tapered protruding square. The tapered protrudingsquare usually is about ½″ to ⅝″ in length. The crank arm has a matingtapered square cavity formed into one end of the crank arm. Theattachment of the crank arm to the spindle is achieved by pressing thetapered square cavity of the crank arm over the tapered squareprotrusion of the spindle. This press fit typically relies on distortionat the points of contact between the crank and the spindle to hold thecrank arm engaged with the spindle. A nut or bolt is also typicallytightened against the outer portion of the crank arm to hold the crankarm onto the spindle.

While the tapered square configuration may seem at first glance a viableand economical method of attaching the crank arms to the spindle, itsuffers in one major area. Although the tapered square may adequatelytransfer the torque from the rider to drive system, it does not do avery good job of preventing the crank arm from rocking or oscillating onthe spindle. This oscillating motion in which the crank arm rocksindependently of the spindle occurs because of the excessive, andconstantly changing loads imposed on the crank system.

With continued use, the oscillating motion may deform the shape of thetapered square connection system. Once enough deformation occurs, thecrank arms become useless. There are shapes other than tapered squaresthat are currently used to transfer of torque between the crank arm andthe spindle such as a spline or a tapered spline. Some include a splinein conjunction with a clamping arrangement that further tightens thesplined portion of the crank arm around the mating splined portion ofthe spindle. Regardless of the shape used in transferring torque fromthe crank arm through the spindle to the other crank arm, all of thesystems could be improved through a system that would eliminate theindependent oscillating movement of the crank arms on the spindle.

Additionally, with the tapered square configuration, a crank arm pulleris typically required in order to remove the crank arms from thespindle. This is a difficult and time consuming procedure. Manybicyclists are not willing to take on this procedure and therefore thisconfiguration discourages the proper servicing of the spindle componentssuch as spindle bearings. Also, in the case of racing bikes, a brokencrank arm or spindle of this type during the course of a race virtuallyinsures that the racer is out of the race due to the time required tochange the spindle or crank arm.

The present invention discloses an improved crank arm/spindle connectionarrangement that utilizes two spaced apart load bearing surfaces forinterconnecting two separate spindle portions. The two spaced apart loadbearing surfaces provide a stabilized connection arrangement forinterconnecting the two spindle portions. A novel spline arrangement isalso disclosed for interconnecting the two spindle portions. This twopiece spindle arrangement eliminates the conventional connection pointsbetween each of the crank arms and the spindle.

Another problem with conventional crank arm systems is that the chainrings that are driven by the crank arms are typically attached to theinside of the crank arms. Because of this configuration, the crank armtypically needs to be removed in order to remove the chain rings. Asmentioned above, since a crank puller is typically required to removethe crank arm, it is difficult to quickly remove and replace a chainring. The present invention discloses a quick change chain ringarrangement that allows the chain ring to be removed and replacedwithout requiring the crank arm to be removed.

In conventional crank assemblies, the chain rings are typically fixed tothe associated crank arm as mentioned above. Because of this, it can bedifficult to properly align the chain rings with other bicyclecomponents such as a front derailleur. Often times, a specialty bike isassembled from components provided by a variety of manufacturers. Thesemanufacturers often have varying spacing and positioning requirementsfor their components. This further contributes to the difficulties inproperly aligning the various components of the bicycle. The presentinvention discloses a chain ring alignment system that allows theposition of the chain rings of the crank assembly to be adjusted alongthe crank assembly rotational axis.

In many circumstances, it would be desirable to provide crank arms witha larger crank arm radius. This would provide greater leverage to therider and allow more driving force to be exerted for a given amount ofeffort from the rider. However, the length of the crank arms ofconventional crank assemblies are limited by the ground clearance of thecrank arms. Also, as the crank arm radius is increased, the rider mustmove the pedals around a larger circumference which takes a longeramount of time. This takes away from the leverage benefits provided bylonger crank arms. The present invention discloses a variable lengthcrank arm arrangement that allows the crank arm length to be increasedduring the downward stroke of the crank arm rotation and shortenedduring the upward stroke. This increases the leverage available to therider during the downward stroke of the pedal rotation as would be thecase with a longer fixed crank arm However, the variable length crankarm reduces the distance the pedal is required to travel during a crankassembly rotation compared to a longer fixed crank. Furthermore, thevariable length crank arm arrangement may be configured to increase theground clearance of the crank assembly.

Another problem associated with conventional crank assemblies involvescurrently available arrangements for connecting a bicycle shoe to apedal. Typically, bicycle shoes include a clip for attaching the shoe tothe pedal. These clips are normally engaged by properly aligning theclip on the shoe with an associated protrusion on one of the flats ofthe pedal. This arrangement requires the rider to first position thepedal with the protrusion facing up and then align the clip on the shoewith the protrusion before engaging the clip. This can be an awkwardprocedure that can at times be dangerous. Also, once clipped in, theconnection may be difficult to quickly disengage causing potentialsafety concerns. The present invention discloses a bicycle shoe to pedalconnection arrangement that simplifies the process of engaging anddisengaging the shoe to pedal connection.

SUMMARY OF THE INVENTION

As will be described in more detail hereinafter a bicycle crank assemblyfor use on a bicycle is herein disclosed. In one embodiment of thepresent invention, the crank arm assembly includes a spindle connectionarrangement for connecting a crank arm to the bicycle crank armassembly. The spindle connection arrangement is also used to connect thecrank arm assembly to a bicycle frame along a spindle rotational axisaround which the crank arm assembly is intended to rotated when thespindle connection arrangement is connected to the bicycle frame.

The spindle connection arrangement includes a first spindle portionfixed to and extending outward from the crank arm along the spindlerotational axis. The first spindle portion has two load bearing surfacesthat are spaced apart from one another along the length of the spindlerotational axis. A second spindle portion also has two load bearingsurfaces that are spaced apart from one another along the spindlerotational axis. The second spindle portion is configured toconcentrically mate with the first spindle portion about the spindlerotational axis.

The spindle connection arrangement also includes a connection devicethat connects the first spindle portion to the second spindle portionsuch that the two load bearing surfaces of the first portion of thespindle arrangement each engage an associated one of the two loadbearing surfaces of the second spindle portion. The two pairs ofengaging, spaced apart, load bearing surfaces provide interconnectingsurfaces for connecting the first and second spindle portions, therebypreventing one spindle portion from oscillating independently from theother and preventing the spindle portions from becoming misaligned fromone another when the two spindle portions are connected using theconnection device.

In one version of the spindle connection arrangement, the spindleconnection arrangement includes at least one tapered bore formed intoone of the pairs of load bearing surfaces of the spindle connectionarrangement. The tapered bore has a longitudinal axis that extends alongthe engaging load bearing surfaces of the first and second spindleportions such that approximately half of the tapered bore is formedlongitudinally into the load bearing surface of the first spindleportion and half of the tapered bore is formed longitudinally into theload bearing surface of the second spindle portion. In this version, theconnection device is a replaceable spline device. The spline deviceincludes at least one tapered pin held in the tapered bore so as toprevent the crank arm from rotating independently of the second spindleportion. The spline device also includes a tapered pin retention devicefor holding the tapered pin within the tapered bore.

In another version of the spindle connection arrangement, the spindleconnection arrangement includes a plurality of tapered bores formed intoone of the pairs of load bearing surfaces of the spindle connectionarrangement and the spline device includes a plurality of associatedtapered pins. In this version, the number of tapered bores andassociated tapered pins is a multiple of three. Also, the tapered pinretention device includes a washer having holes cut into a peripheraledge portion of the washer. The holes are formed such that the outsidediameter of the holes are a size that allows the tapered pins to bepressed into the holes and retained by the washer to allow the taperedpins to be simultaneously inserted into the tapered bores for ease ofassembly. The tapered pin retention device also includes a biasingtriangular shaped piece for every three tapered pins. The triangularshaped piece is biased against a top end of each of its three associatedtapered pins to put equal pressure on each tapered pin and retain itsthree associated tapered pins within their tapered bores.

In another embodiment of the invention, the above described splinedevice is used in a spline arrangement for interconnecting a drivemember and a driven member such that the drive member is able torotationally drive the driven member about a given rotational axis. Inthis embodiment, the spline arrangement includes a first annular drivemember engaging surface located on the drive member. The first annulardrive member engaging surface is oriented generally parallel with andextending along the given rotational axis. The spline arrangement alsoincludes a first annular driven member engaging surface located on thedriven member. The first annular driven member engaging surface beingoriented generally parallel with and extending along the givenrotational axis. The first annular driven member engaging surface isconfigured to concentrically mate with the first annular drive memberengaging surface.

In accordance with the invention, the driven member and the drive memberhave at least one tapered bore formed into the first annular engagingsurfaces of the drive member and driven member. The tapered bore has alongitudinal axis that extends along the concentrically mating firstannular engaging surfaces of the drive and driven member such thatapproximately half of the tapered bore is formed longitudinally into thefirst drive member engaging surface and half of the tapered bore isformed longitudinally into the first driven member engaging surface. Thespline arrangement further includes at least one tapered pin configuredto fit within the tapered bore so as to prevent the drive member fromrotating independently of the driven member. A tapered pin retentiondevice is used to hold the tapered pin within the tapered bore.

In one version of the spline arrangement, the driven member and thedrive member have a plurality of tapered bores formed into the firstannular engaging surfaces of the drive member and driven member and thespline arrangement includes a plurality of tapered pins. In thisversion, the number of tapered pins is a multiple of three. Also, thetapered pin retention device includes a washer having holes cut into aperipheral edge portion of the washer. The holes are formed such thatthe outside diameter of the holes are a size that allows the taperedpins to be pressed into the holes and retained by the washer to allowthe tapered pins to be simultaneously inserted into the tapered boresfor ease of assembly. The tapered pin retention device further includesa biasing triangular shaped piece for every three tapered pins. Thetriangular shaped piece is biased against a top end of each of its threeassociated tapered pins to put equal pressure on each tapered pin andretain its three associated tapered pins within their tapered bores.

In another version of the spline arrangement, the spline arrangementfurther includes a second annular drive member engaging surface locatedon the drive member. The second annular drive member engaging surface isoriented generally parallel with and extending along the givenrotational axis and the second annular drive member engaging surface isspaced apart from the first annular drive member engaging surface. Asecond annular driven member engaging surface is located on the drivenmember. The second annular driven member engaging surface is orientedgenerally parallel with and extending along the given rotational axisand the second annular driven member engaging surface is spaced apartfrom the first annular driven member engaging surface. The secondannular driven member engaging surface is configured to concentricallymate with the second annular drive member engaging surface, therebyproviding two pairs of spaced apart engaging surfaces between the drivemember and the driven member.

A quick change chain ring arrangement for use on a bicycle crankassembly having a pair of crank arms, a pair of pedals, and a crankassembly rotational axis around which the crank assembly is intended torotate when the crank assembly is connected to a bicycle frame is alsodisclosed. The quick change chain ring arrangement includes a chain ringadapter that attaches to the crank assembly such that the adapterrotates with the crank assembly about the crank assembly rotationalaxis. A removable chain ring is attached to the chain ring adapter. Thechain ring has an inside diameter large enough that the chain ring maybe removed from the bicycle without requiring the removal of any of thecrank arms or pedals. A removable connecting device retains theremovable chain ring on the chain ring adapter. The removable connectingdevice is configured such that it may be removed without requiring theremoval of any of the crank arms or pedals.

In one version of the quick change chain ring arrangement, the chainring adapter is a splined adapter that attaches to the crank assemblysuch that the splined adapter rotates with the crank assembly about thecrank assembly rotational axis. The chain ring has a spline shape thatmates with the splined adapter such that the chain ring is driven in arotational manner by the splined adapter about the crank assemblyrotational axis. However, the chain ring is free to be removed whenpulled in a direction parallel with the crank assembly rotational axis,thereby allowing the removal of the chain ring without requiring theremoval of either of the crank arms of the crank assembly. In thisversion, a removable threaded ring threads onto the splined adapter in amanner that compresses the chain ring against the splined adapter. Thisthreaded ring holds the spline shape of the chain ring engaged with thesplined adapter and preventing unwanted movement of the chain ring in adirection parallel to the crank assembly rotational axis.

A chain ring alignment system for use on a bicycle crank assembly havinga first and a second crank arm and a crank assembly rotational axisaround which the crank assembly is intended to rotate when the crankassembly is connected to a bicycle frame is also disclosed. The chainring alignment system includes a chain ring adapter for supporting achain ring. The chain ring adapter is mounted to the crank assembly forrotation with the crank assembly about the crank assembly rotationalaxis. The chain ring adapter is axially movable along the crank assemblyrotational axis between a retracted position and an extended position. Adriving mechanism is connected to the first crank arm for rotationallydriving the chain ring adapter about the crank assembly rotational axiswhile allowing the chain ring adapter to move axially from the retractedposition in which the chain ring is furthest from the first crank arm tothe extended position in which the chain ring is closest to the firstcrank arm. An adjusting device is provided for moving the chain ringadapter axially along the crank assembly rotational axis between theretracted position and the extended position, independently from thecrank arms. This enables the proper alignment of the chain ring adapterrelative to other components on the bicycle without requiring the axialmovement of the crank arms and without requiring the crank arms to bepositioned off center with reference to the bicycle frame.

In one version of the chain ring alignment system, the chain ringadapter includes a threaded portion having a longitudinal axis parallelto the crank assembly rotational axis. The alignment system alsoincludes at least one hole having a longitudinal axis parallel to thecrank assembly rotational axis. The driving mechanism includes at leastone driving boss that protrudes out from the first crank arm. The bosshas a longitudinal axis that extends parallel to the crank assemblyrotational axis. The boss is configured to engage the hole in the chainring adapter in order to be capable of rotationally driving the chainring adapter about the crank assembly rotational axis with the rotationof the crank assembly. The boss also allows axial movement of the chainring adapter along the crank assembly rotational axis from the retractedposition to the extended position. In this version, the adjusting deviceincludes a threaded adjustment dial and a retaining ring the threadedadjusting dial has threads that match the threaded portion of the chainring adapter. The threaded adjustment dial is configured to move thechain ring adapter from the retracted position to the extended positionas the thread ed adjustment dial is turned into the matching threads ofthe chain ring adapter. The retainer ring is fixed to the crank assemblysuch that the threaded adjustment dial is prevented from separating fromthe threaded portion of the chain ring adapter when the chain ringalignment system is attached to the crank assembly.

A variable length crank arm arrangement for use on a bicycle is alsodisclosed. Me variable length crank arm arrangement includes a spindlehaving a spindle bearing surface for mounting the spindle to the bicyclesuch that the spindle is free to rotate about a spindle rotational axis.A fixed crank arm, having a longitudinal axis extending substantiallyperpendicular to the spindle rotational axis, is fixed to the spindlefor rotation with the spindle about the spindle rotational axis. Afloating crank arm, having a longitudinal axis, is slidably connected tothe fixed crank arm to allow the floating crank arm to move in a linearmotion along the longitudinal axis of the fixed crank arm whilemaintaining a common longitudinal axis with the fixed crank arm. Acontrol bracket is fixed to the bicycle. The control bracket may be aseparate piece that is attached to a conventional bicycle frame, oralternatively, the control bracket may be provided as part of thebicycle frame.

The control bracket includes a rotational control bearing surface thatdefines a control rotational axis that is parallel with, but spacedapart from, the spindle rotational axis. The control bearing surface hasa control bearing radius with the control bearing surface beingpositioned such that the spindle rotational axis fall s within thecontrol bearing radius when viewed in a plane perpendicular to thespindle rotational axis. A control arm is attached to the controlbracket for rotation about the control axis along the control bearingsurface. The control arm is rotatably attached to the floating crank armsuch that the longitudinal axis of the floating crank arm is able toremain perpendicular to the spindle rotational ax is.

With the above described variable length crank arm arrangementconfiguration described above, the floating crank arm causes the controlarm to rotate about the control rotational axis and causes the fixedcrank arm to rotate about the spindle rotational axis as the floatingcrank arm is rotate d about the control rotational axis. this causes thefloating crank arm to move back and forth along the longitudinal axis ofthe fixed crank arm relative to the spindle rotational axis. The overalllength of the combination of the fixed crank arm and the floating crankarm varies along their common longitudinal axis by a distance equal totwice the spacing between the control rotational axis and the spindlerotational axis.

In one version of the variable length crank arm, the control rotationalaxis is spaced apart from the spindle rotational axis by a distance inthe range of about ½″ to ⅞. In this version, the control rotational axisis located above, relative to the ground when the bicycle is in theupright position, and in front of the spindle rotational axis. Thiscauses the overall length of the combination of the fixed crank arm andthe floating crank arm to be greatest during the downward stroke of thecrank arm arrangement as the bicycle is being ridden. This also causesthe ground clearance of the crank arm arrangement to be increasedcompared to a bicycle using a conventional crank arm arrangement.

A pedal connection arrangement for holding a bicycle rider's footattached to a bicycle pedal that is used to drive a bicycle crank armhaving a crank arm longitudinal axis is also disclosed. The bicycleconnection arrangement includes a pedal having a pedal longitudinalaxis. The pedal is connected to the crank arm with the pedallongitudinal axis substantially perpendicular to the crank armlongitudinal axis. The pedal connection arrangement also includes abicycle shoe having a gripping arrangement attached to the shoe. Thegripping arrangement has a longitudinal axis that runs generally alongthe ball of the shoe in a plane parallel to the sole of the shoe andperpendicular to a line extending from the toe of the shoe through theheel of the shoe. The gripping arrangement is configured such that thegripping arrangement grips the pedal when the gripping arrangement ispositioned adjacent to the pedal with the longitudinal axis of thegripping arrangement aligned with the longitudinal axis of the pedal andmoved along the common longitudinal axes of the gripping arrangement andthe pedal to engage the pedal.

In one version of the pedal connection, the pedal has a radiallysymmetrical cross sectional shape along the pedal longitudinal axis andthe gripping arrangement has a mating radially symmetrical cavity. Thisconfiguration allows the gripping arrangement to be connected to thepedal with the pedal in any position without regard for the rotationalposition of the pedal about the pedal longitudinal axis. The pedal mayhave a shape selected from the group of a cylindrical shape, a sphericalshape, and a combination of a cylindrical shape and a spherical shapeand the gripping arrangement has a mating cavity. In one specificembodiment, the pedal has a spherical shape and the gripping arrangementhas a mating spherical cavity. This allows the pedal to be securelyconnected to the shoe, yet remain free to swivel or pivot to a certaindegree, thereby giving more flexibility for maneuverability to the riderwhile maintaining positive contact between the shoe and the pedal.

The gripping arrangement may be an independently formed gripping devicethat is attached to the bicycle shoe. Alternatively, the grippingarrangement may be formed as part of the bicycle shoe. The grippingarrangement may also be made from a pliable material that allows therider to release the shoe from the pedal by bending their toes up out ofnatural position causing the gripping arrangement to flex. This flexingof the foot causes the gripping arrangement to expand on the bottom ofthe shoe and therefore causes the gripping arrangement to release thepedal.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention may best be understood byreference to the following description of the presently preferredembodiments together with the accompanying drawings in which:

FIG. 1 is a diagrammatic perspective view of a first embodiment of abicycle crank arm assembly designed in accordance with the invention.

FIG. 2 is exploded view of the crank arm assembly of FIG. 1.

FIG. 3 is a cross sectional view of the crank arm assembly of FIG. 1taken along section line 4—4.

FIG. 4 is a cross sectional view of the spindle portions of the crankarm assembly of FIG. 1 taken along section line 4—4.

FIG. 5 is a partially exploded and partially cut away view of the crankarm assembly of FIG. 1 illustrating one embodiment of a connectiondevice for connecting the spindle portions.

FIG. 6A is a partially exploded view of one embodiment of a tapered pinretention device in accordance with the invention.

FIG. 6B is an exploded view of one embodiment of a biasing arrangementin accordance with the invention for exerting an equal amount ofpressure on each of the tapered pins of the tapered pin retaining deviceof FIG. 6A.

FIG. 7 is a cross sectional view of connection device of FIG. 5.

FIG. 8 is a perspective view of one embodiment of a variable lengthcrank arm arrangement designed in accordance with the invention.

FIG. 9 is a second perspective view from a different angle of thevariable length crank arm arrangement of FIG. 8.

FIG. 10 is a third perspective view of a portion of the variable lengthcrank arm arrangement of FIG. 8.

FIG. 11 is a plan view of a pedal designed in accordance with theinvention.

FIG. 12 is a perspective view of a bicycle shoe designed in accordancewith the invention.

FIG. 13 is a cross sectional perspective view of one embodiment of asplined bearing cartridge assembly designed in accordance with theinvention.

FIG. 14 is a partially exploded view of the splined bearing cartridgeassembly of FIG. 13.

DETAILED DESCRIPTION

An invention is described for providing an improved bicycle crank. Inthe following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be obvious, however, to one skilled in the art, that the presentinvention may be embodied in a wide variety of specific configurations.Also, well known bicycle components and hardware have not been describedin detail in order not to unnecessarily obscure the present invention.

Turning to the drawings, wherein like components are designated by likereference numerals throughout the various figures, attention isinitially directed to FIGS. 1-4. These figures illustrates a variousviews of a first embodiment of a crank arm assembly 100 designed inaccordance with the invention. FIG. 1 is a perspective view of theassembly, FIG. 2 is an exploded view of the assembly, FIG. 3 is a crosssectional view of the assembly, and FIG. 4 is a cross sectional detailview of the spindle portions of the assembly.

Crank arm assembly 100 includes a spindle connection arrangement 102 forconnecting a crank arm 104 to bicycle crank arm assembly 100. Spindleconnection arrangement 102 is also used to connect crank arm assembly100 to a bicycle frame along a spindle rotational axis 106 around whichcrank arm assembly 100 is intended to rotated when spindle connectionarrangement 102 is connected to a bicycle frame.

Spindle connection arrangement 102 includes a first spindle portion 108,shown in FIGS. 2-4, fixed to and extending outward from crank arm 104along spindle rotational axis 106. First spindle portion 108 has twoload bearing surfaces 110 and 112, shown in FIGS. 3 and 4, that arespaced apart from one another along the length of spindle rotationalaxis 106. A second spindle portion 114 also has two load bearingsurfaces 116 and 118 that are spaced apart from one another alongspindle rotational axis 106. As shown best in FIGS. 3 and 4, secondspindle portion 114 is configured to concentrically mate with firstspindle portion 108 about spindle rotational axis 106. In the embodimentshown, second spindle portion 114 is provided as a spindle portion thatextends outwardly from a second crank arm 115.

As will be described in more detail hereinafter, spindle connectionarrangement 102 also includes a connection device 120 (shown in FIG. 3)that connects first spindle portion 108 to second spindle portion 114such that the two load bearing surfaces 110 and 112 of first spindleportion 108 each engage an associated one of the two load bearingsurfaces 116 and 118 of second spindle portion 114. The two pairs ofengaging, spaced apart, load bearing surfaces provide interconnectingsurfaces for connecting the first and second spindle portions. These twospaced apart load bearing surfaces prevent one spindle portion fromoscillating independently from the other and prevent the spindleportions from becoming misaligned from one another when the two spindleportions are connected using connection device 120.

In the embodiment shown, load bearing surfaces 110 and 116 are spacedapart from load bearing surfaces 112 and 118 by an air gap 121 thatensures these two pairs of mating surfaces form two spaced apart loadbearing, engaging surfaces. Although these load bearing surfaces areshown as being separated by an air gap, this is not a requirement of theinvention. Instead, the present invention would equally apply so long asthe two load bearing portions of the load bearing surfaces are spacedapart from one another.

The two spaced apart load bearing surfaces, referred to hereinafter astwo point stabilization, eliminates the conventional connection betweena crank arm and spindle. This two point stabilization approach createsand maintains a secure connection between the crank arm and the spindle.Because the loads imposed on the crank system are distributed over, andshared by two separate, spaced apart load bearing surfaces, the twopoint stabilization approach provides a much more reliable crankarm/spindle connection arrangement compared to conventional methods ofconnecting a crank arm to a spindle.

A spindle connection arrangement in accordance with the inventionprovides the additional benefit that this arrangement may be provided ata lighter weight than conventional spindle configurations withoutsacrificing strength and durability. This is because the loads imposedon the spindle by the crank arms are distributed over the two spacedapart bearing surfaces rather than being concentrated on the taperedsquare protrusion of conventional crank arm spindles. Also, because thesecond spindle portion 114 may be provided as a tube extending from thesecond crank arm 115 as illustrated in FIG. 3, a grease fitting 122 andgrease ports 124 (shown best in FIG. 2) may be easily incorporated intothe design. The grease ports 124 could be positioned to provide greaseto all of the moving parts of the assembly without sacrificing thestrength of the connection arrangement. This would allow regularservicing of the moving parts within the crank assembly withoutrequiring the disassembly of the crank assembly.

Although the spindle connection arrangement illustrated in FIGS. 1-4uses two spindle portions with one portion extending from each of thecrank arms, this is not a requirement of the invention. Instead, thisarrangement could include a three piece spindle. In this case, both ofthe crank arms would have a spindle portion similar to spindle portion108 extending from the crank arm along the spindle rotational axis. Eachof these crank arm spindle portions would attach to a separate, thirdspindle portion using the two point stabilization approach describedabove.

Referring now to FIGS. 5-7, a spline arrangement for connecting spindleportions 108 and 114 of crank assembly 100 will be described. Inaccordance with one aspect of the invention, spindle connectionarrangement 102 includes at least one tapered bore 126 formed into oneof the pairs of load bearing surfaces of spindle connection arrangement102. In the embodiment shown in FIG. 5, six tapered bores 126 are formedinto load bearing surfaces 110 and 116. Each of the tapered bores has alongitudinal axis that extends along the engaging load bearing surface110 of first portion 108 and surface 116 of second spindle portion 114.Approximately half of tapered bores 126 (indicated by reference numeral126 a in FIG. 5) are formed longitudinally into load bearing surface 110of spindle portion 108 and the other half of tapered bores 126(indicated by reference numeral 126 b in FIG. 5) are formedlongitudinally into load bearing surface 116 of spindle portion 114.

In this embodiment, connection device 120 takes the form of areplaceable spline device 128. Spline device 128 includes at least onetapered pin 130 held in an associated tapered bore 126 so as to preventcrank arm 104 from rotating independently of spindle portion 114. In theembodiment being described, spline device 128 includes six tapered pins130. Spline device 128 also includes a tapered pin retention device 132,which will be described in more detail hereinafter, for holding taperedpins 130 within tapered bores 126. Although spline device 128 isdescribed as including six tapered pins, this is not a requirement ofthe invention. Instead, it should be understood that any number oftapered pins may be used and still remain within the scope of theinvention.

One of the main advantages of the tapered pin spline arrangement is thatthe tapered pin spline mechanism is extremely simple and cost effectiveto manufacture compared to other conventional spline arrangements. Theboring operation required to bore the tapered bores can be performedwith a simple drilling or milling machine and a rotary table. Thetapered pins can be run on a screw machine lathe cost effectively.Therefore, sophisticated machining equipment is not required in order toproduce a tapered pin spline arrangement. This reduces the cost ofproducing this type of spline arrangement.

Another advantage of the tapered pin spline arrangement is that taperedpins 126 can be made from a lower strength material than the surroundingarea of the spindle portions. With this configuration, the tapered pinsare able to act as fuses in the event of an overload of stress appliedto the crank set by shearing before permanent damage occurs to thespindle portions. Replacement tapered pins could be provided to the bikeowner at significantly less cost than the cost of replacing the entirecrank set which is required when conventional crank sets fail.

Although connection device 120 has been described as being spline device128, this is not a requirement of the invention. Instead, anyconventional connection device such as a bolt or a threaded stud may beused to hold spindle portion 108 engaged with spindle portion 114 andstill remain within the scope of the invention so long as spindleportions 108 and 114 have two spaced apart bearing surfaces as describedabove.

In the embodiment described above, the number of tapered bores andassociated tapered pins is a multiple of three. This allows the use of atapered pin retaining device 132 in accordance with the invention. Asillustrated in FIGS. 5 and 6A, one embodiment of tapered pin retentiondevice 132 includes a washer 134 having holes or openings 136 cut into aperipheral edge portion 138 of washer 134. Openings 136 are formed suchthat the outside diameter of the openings are a size that allows taperedpins 130 to be pressed into the openings and retained by washer 134.This allows tapered pins 130 to be simultaneously inserted into taperedbores 126 for ease of assembly.

In the embodiment shown, the portions of tapered pins 130 that arepressed into opening 136 have a slightly smaller diameter than theremainder of tapered pins 130. This smaller diameter, indicated byreference numeral 140, assists in holding tapered pins captured withinopenings 136. Also, the smaller diameter portions 140 of tapered pins130 extend along the length of tapered pins 130 for a distance greaterthan the thickness of washer 134. This allows some freedom of movementfor the pins within the washer along the longitudinal axis of thetapered pins. This also forms heads 141 on tapered pins 130 at the endsof tapered pins 130 that are opposite the ends of the tapered pins thatare inserted into tapered bores 126. As will be described immediatelyhereafter, this freedom of movement along the longitudinal axis of thetapered pins helps allow tapered pins 130 to be held within taperedbores 126 with equal amounts of pressure on each tapered pin.

Referring now to FIGS. 6A and 6B, a biasing arrangement 142 designed inaccordance with the invention will be described. In the embodimentshown, tapered pin retention device 132 also includes a biasingarrangement 142 for placing an equal amount of pressure on each of heads141 of tapered pins 130. Biasing arrangement 142 includes a fastener143, such as a bolt, that is used to draw biasing arrangement 142against heads 141 of tapered pins 130. Biasing arrangement 142 alsoincludes a triangular shaped piece for every three tapered pins. In thiscase, since six tapered pins are used, two triangular pieces 144 and 146are used. Triangular shaped piece 144 and 146 are separated by twobelleville spring washers 148. Triangular piece 146 and the head offastener 143 are also separated by a belleville spring washer 148.Washers 148 are sloped, as shown best in FIG. 7, so as to allowtriangular pieces 144 and 146 some degree of freedom to wobble relativeto the longitudinal axis of fastener 143 which, in this case, coincideswith the spindle rotational axis 106. This helps allows triangularpieces 144 and 146 to exert an equal amount of pressure on each taperedpin.

As illustrated in FIG. 6B, triangular piece 146 has protrusions at thecorners acting as locators for triangular piece 144 with no protrusions.This keeps the triangular pieces aligned with respect to the spacing ofthe tapered pins. Therefore, only one step is required to align thetriangles with the heads of the tapered pins.

The reason for the triangles is to assure that equal pressure is placedon all pins. Since three points define a plane, theoretically, if threepins were slightly higher than the rest, these three pins would receivethe majority of the pressure if a simple bolt and washer were used tocompress all six of the tapered pins. This may not be a problem if onlythree tapered pins were used, however, the triangular shape stilldirects bolt pressure better than a conventional washer and is easier toposition properly on the tapered pins.

Biasing arrangement 142 is designed so that triangular piece 144 willtouch its three tapered pins first since it is originally slightlycloser to the heads of the pins than triangular piece 146. Springwashers 148 take up the slack and put pressure on triangular piece 144until the two triangular pieces share the same approximate level. Asfastener 143 is tightened further, both triangles are then underpressure. Both triangular pieces, while they get there pressure from thesame bolt, are able to rock independently of each other to adjust toslight tapered pin height variations because of the belleville springwashers. The spring washers also apply back pressure on the head offastener 143 which helps prevent it from loosening on its own. With thisarrangement, all of the tapered pins receive substantially an equalamount of pressure, thereby insuring that each of the tapered pins isheld firmly within tapered bores 126.

Although tapered pin retention device 132 is described as includingbiasing arrangement 142 and washer 134 for holding pins 130 together,these components are not requirements of the invention. Instead, anyappropriate pin retention mechanism may be utilized to hold tapered pins130 within tapered bores 126 and still remain within the scope of theinvention.

Although the above described spline device 128 has been described asbeing used to connect the two spindle portions of a bicycle crank armassembly, it should be understood that this novel spline arrangement maybe used to connect a wide variety of rotational members. For example, inanother embodiment of the invention, the above described spline deviceis used in a spline arrangement for interconnecting a drive member and adriven member such that the drive member is able to rotationally drivethe driven member about a given rotational axis. Using the example ofthe above described spindle arrangement, the drive member may be thefirst spindle portion 108 protruding from crank arm 104 and the drivenmember may be second spline portion 114.

Referring back to FIGS. 1-3, a quick change chain ring arrangement 150in accordance with the invention for use on a bicycle crank arm assemblysuch as crank assembly 100 will be described. As mentioned above, crankarm assembly 100 includes two crank arms 104 and 115 that rotate aboutspindle rotational axis 106. As best shown in FIG. 2, quick change chainring arrangement 150 includes a chain ring adapter 152 that attaches tocrank assembly 100 such that adapter 152 rotates with the crank assemblyabout spindle rotational axis 106. A removable chain ring support 154 isattached to chain ring adapter 152. Chain ring support 154 has an insidediameter large enough that it may be removed from the bicycle withoutrequiring the removal of any of the crank arms or pedals. A removableconnecting device 156 retains removable chain ring support 154 on chainring adapter 152. Removable connecting device 156 is also configuredsuch that it may be removed without requiring the removal of any of thecrank arms or pedals.

In the embodiment illustrated in FIGS. 1-3, quick change chain ringarrangement 150 uses a splined chain ring adapter 152 that attaches tocrank assembly 100 such that the splined adapter rotates with the crankassembly about spindle rotational axis 106. Chain ring support 154 has aspline shape that mates with splined adapter 152 such that chain ringsupport 154 is driven in a rotational manner by splined chain ringadapter 152 about spindle rotational axis 106. In this embodiment,removable connecting device 156 takes the form of a removable threadedring that threads into splined adapter 152 in a manner that compresseschain ring support 154 against splined adapter 152. This threaded ringholds the spline shape of the chain ring engaged with the splinedadapter and prevents unwanted movement of the chain ring in a directionparallel to the spindle rotational axis. However, with the threaded ringremoved, the chain ring is free to be removed when pulled in a directionparallel with the crank assembly rotational axis. This allows theremoval of the chain ring without requiring the removal of either of thecrank arms of the crank assembly.

In the embodiment shown, the crank assembly is a mountain bike crankassembly that includes mounting points for three front sprockets. Thequick change chain ring arrangement illustrated allows the outer andmiddle chain rings or sprockets to be removed without removing the crankarm in literally a matter of seconds. This enables the rider to quicklychange the gearing of their bicycle through different sized front chainrings, and encourages the rider to properly clean the main chain ringsto increase life and increase performance through a properly cleaned andlubricated chain rings.

Still referring to FIGS. 1-3, a chain ring alignment system 160 designedin accordance with the invention will now be described. Chain ringalignment system 160 includes a chain ring adapter, such as chain ringadapter 152 described above, for supporting a chain ring. Chain ringadapter 152 is mounted to crank assembly 100 for rotation with the crankassembly about spindle rotational axis 106. However, chain ring adapter152 is axially movable along spindle rotational axis 106 between aretracted position and an extended position. A driving mechanism 162 isconnected to crank arm 115 for rotationally driving chain ring adapter152 about spindle rotational axis 106 while allowing the chain ringadapter to move axially from the retracted position in which chain ringadapter 152 is furthest from crank arm 115 to the extended position inwhich chain ring adapter 152 is closest to crank arm 152. An adjustingdevice 164 is provided for moving chain ring adapter 152 axially alongspindle rotational axis 106 between the retracted position and theextended position, independently from crank arm 115. This enables theproper alignment of chain ring adapter 152 relative to other componentson the bicycle without requiring the axial movement of the crank armsand without requiring the crank arms to be positioned off center withreference to the bicycle frame.

In the embodiment illustrated in FIGS. 1-3, chain ring adapter 152includes a threaded portion having a longitudinal axis about spindlerotational axis 106. In the embodiment shown, the threaded portion isactually provided as a separate threaded ring 167 that is press fit intochain ring adapter 152. Chain ring adapter 152 also includes two drivingholes 166 having a longitudinal axis parallel spindle rotational axis106. Driving mechanism 162 includes two driving bosses 168 that protrudeout from crank arm 115. The bosses have a longitudinal axis that extendsparallel to the crank assembly rotational axis. Bosses 168 areconfigured to engage driving holes 166 in chain ring adapter 152 inorder to be capable of rotationally driving chain ring adapter 152 aboutspindle rotational axis 106 with the rotation of crank assembly 100. Thebosses also allow axial movement of the chain ring adapter along thespindle rotational axis from the retracted position to the extendedposition. Adjusting device 164 takes the form of a threaded adjustmentdial 170 and a retaining flange piece 172. Threaded adjusting dial 170has threads that match the threaded portion 166 of chain ring adapter152. Threaded adjustment dial 170 is configured to move chain ringadapter 152 between the retracted position to the extended position asindicated by arrow 174 in FIG. 2 when threaded adjustment dial 170 isturned into and out of the matching threads of chain ring adapter 152.Retainer flange piece 172 is press fit onto spindle portion 114 suchthat threaded adjustment dial 170 is prevented from separating fromthreaded ring 167 of chain ring adapter 152 when the chain ringalignment system is attached to the crank assembly.

The above described chain ring alignment system allows a rider to adjusttheir chain rings without a tool. This uniquely allows the chain ring tomove independently of the crank arm and spindle, thus enabling the crankarms and spindle to remain perfectly centered in reference to the centerof the bicycle frame. Aside from adjusting the linear position of thechain rings, the chain ring alignment system also provides a uniqueconnection between the chain rings and the driving crank arm. Unlike allconventional crank systems, the chain rings of the chain ring alignmentsystem of the present invention are not bolted directly or clamped tothe driving crank arm. Instead, the chain ring is driven by bosses 168.This allows the alignment of the chain rings to stay perpendicular tothe spindle rotational axis, and remain virtually unaffected by anycrank arm flex that can oscillate the chain rings.

Referring now to FIGS. 8-10, a variable length crank arm arrangement 200designed in accordance with the invention and for use on a bicycle crankarm assembly 202 is also disclosed. Variable length crank armarrangement 200 includes a spindle 204 for attaching the crank assemblyto a bicycle frame 206. Spindle 204 has a spindle bearing surface 208,shown best in FIG. 10, for mounting spindle 204 to the bicycle such thatthe spindle is free to rotate about a spindle rotational axis 210. Afixed crank arm 212 (not shown in FIG. 10), having a longitudinal axis214 (shown in FIG. 8) extending substantially perpendicular to spindlerotational axis 210, is fixed to spindle 204 for rotation with spindle204 about spindle rotational axis 210. A floating crank arm 216, havinga longitudinal axis that coincides with longitudinal axis 214 of fixedcrank arm 212, is slidably connected to fixed crank arm 212 to allowfloating crank arm 216 to move in a linear motion along longitudinalaxis 214 of fixed crank arm 212 while maintaining a common longitudinalaxis with fixed crank arm 212. A control bracket 218 (shown best in FIG.9) is fixed to bicycle frame 206. Control bracket 218 may be a separatepiece that is attached to a conventional bicycle frame as illustrated inFIG. 9, or alternatively, the control bracket may be provided as anintegral part of the of the bicycle frame as illustrated in FIG. 8.

Referring now to FIGS. 9 and 10, control bracket 218 includes arotational control bearing surface 220 that defines a control rotationalaxis 222 that is parallel with, but spaced apart from, spindlerotational axis 210. Control bearing surface 220 has a control bearingradius 224 with control bearing surface 220 being positioned such thatspindle rotational axis 210 falls within control bearing radius 224 whenviewed in a plane perpendicular to spindle rotational axis 210. Acontrol arm 226 is attached to control bracket 218 for rotation aboutcontrol axis 222 along control bearing surface 220. Control arm 226 isrotatably attached to floating crank arm 216 such that the longitudinalaxis of the floating crank arm is able to remain perpendicular tospindle rotational axis 210.

With the variable length crank arm arrangement configuration describedabove, floating crank arm 216 causes control arm 226 to rotate aboutcontrol rotational axis 222 and causes fixed crank arm 212 to rotateabout spindle rotational axis 210 as floating crank arm 216 is rotatedabout control rotational axis 222 by a rider. This causes floating crankarm 216 to move back and forth along longitudinal axis 214 of fixedcrank arm 212 relative to spindle rotational axis 210. Due to thespacing between spindle rotational axis 210 and control rotational axis222, floating crank arm 216 pivots slightly back and forth relative tocontrol arm 226 as the variable length crank arm arrangement is rotatedby the rider. The overall length of the combination of the fixed crankarm and the floating crank arm varies along their common longitudinalaxis by a distance equal to twice the spacing between the controlrotational axis and the spindle rotational axis.

In one embodiment of the variable length crank arm, control rotationalaxis 222 is spaced apart from spindle rotational axis 210 by a distancein the range of about ½″ to ⅞″. In this embodiment, control rotationalaxis 222 is located above and toward the front of the bike relative tospindle rotational axis 210. This causes the overall length of thecombination of fixed crank arm 212 and floating crank arm 216 to begreatest during the downward stroke of the crank arm arrangement as thebicycle is being ridden. This also causes the overall length of thecombination of fixed crank arm 212 and floating crank arm 216 to beleast during the upward stroke of the crank arm arrangement. Therefore,this configuration provides most of the leverage benefits of a longercrank arm with no added circumference. This leverage advantage may beincreased by increasing the spacing between the control rotational axisand the spindle rotational axis.

Besides the increase in power, this variable length crank armarrangement, may be configured to increase the ground clearance of thecrank assembly. This is accomplished by locating the control rotationalaxis above the spindle rotational axis. An added benefit of theincreased ground clearance is that this system allows for moresuspension travel on a suspension bicycle where often times moresuspension travel is desired, yet the ground clearance of the pedals isthe limiting factor.

One of the unique features of the variable length crank arm arrangementof the invention lies in the fact that it utilizes a multiple bearinghousing with eccentric bearing axis. This is a simple configuration thatcan either be adapted to current bicycle frames as shown in FIG. 9 orincorporated in to the frame or sub-frame of bicycles in the future asillustrated in FIG. 8. This configuration also provides a very durableand stable configuration due to the positioning of the spindlerotational axis within the radius of the larger control arm bearingsurface and due to the relatively few pieces required to provide thearrangement.

Referring now to FIGS. 8, 11, and 12, a pedal connection arrangementdesigned in accordance with the invention will be described. FIG. 8illustrates a pedal 300 attached to the variable crank arm arrangementdescribed above. FIG. 11 is a plan view of pedal 300. And, FIG. 12illustrates a bicycle shoe 302 designed in accordance with the inventionthat is configured to attach to pedal 300.

As illustrated by FIG. 12, the pedal connection arrangement of theinvention is designed to hold a bicycle shoe attached to a bicyclepedal. As is the case for conventional bicycles, pedal 300 is used todrive a bicycle crank arm having a crank arm longitudinal axis. Pedal300 has a pedal longitudinal axis 304. The pedal is connected to a crankarm, such as variable length crank arm arrangement 200 of FIG. 8, withpedal longitudinal axis 304 substantially perpendicular to the crank armlongitudinal axis 214. The pedal connection arrangement also includesbicycle shoe 302 having a gripping arrangement 306 attached to the shoe.Gripping arrangement 306 has a longitudinal axis, also indicated byreference numeral 304 in FIG. 12, that runs generally along the ball ofthe shoe in a plane parallel to the sole of the shoe and perpendicularto a line extending from the toe of the shoe through the heel of theshoe. Gripping arrangement 306 is configured such that the grippingarrangement grips pedal 300 when gripping arrangement 308 is positionedadjacent to pedal 300 with longitudinal axis 304 of gripping arrangement306 aligned with longitudinal axis 304 of pedal 300 and then moved alongthe common longitudinal axes 304 of gripping arrangement 306 and pedal300 to engage pedal 300 as indicated by arrow 308.

In the embodiment of the pedal connection arrangement shown, pedal 300has a radially symmetrical cross sectional shape along pedallongitudinal axis 304 and gripping arrangement 306 has a mating radiallysymmetrical cavity 310. This configuration allows gripping arrangement306 to be connected to pedal 300 with pedal 300 in any position withoutregard for the rotational position of the pedal about the pedallongitudinal axis. Pedal 300 may have a shape selected from the group ofa cylindrical shape, a spherical shape, and a combination of acylindrical shape and a spherical shape. As mentioned above, grippingarrangement 306 has a similarly mating cavity. In the specificembodiment shown, the pedal has a central spherical shape 312 andgripping arrangement 306 has a mating spherical cavity 314. This allowsthe pedal to be securely connected to the shoe, yet remain free toswivel or pivot to a certain degree, thereby giving more flexibility formaneuverability to the rider while maintaining positive contact betweenthe shoe and the pedal.

Gripping arrangement 306 may be an independently formed gripping deviceas indicated by dashed lines 316 that is attached to a separate bicycleshoe indicted by dashed line 318. Alternatively, the grippingarrangement may be formed as part of bicycle shoe 302 as describedabove. Gripping arrangement 306 may also be made from a pliable materialthat allows the rider to release the shoe from the pedal by bending thetoe of the shoe up out of natural position as indicated by arrow 318 anddashed line 320 in FIG. 12. This causes gripping arrangement 306 toflex. This flexing of the foot causes gripping arrangement 306 to expandon the bottom of the shoe and therefore causes the gripping arrangementto easily release the pedal. An additional benefit to this pliablematerial is that the rider may also “grip” the pedal more tightly byflexing the tow of the shoe downward. This downward flexing causesgripping arrangement 306 to more tightly grip pedal 300.

Referring again to FIGS. 1-3, a bearing housing arrangement for use on abicycle crank assembly, designed in accordance with the invention, willnow be described. In the embodiment shown, crank assembly 100 includestwo bearing housing arrangements 400 and 402. Bearing housingarrangements 400 and 402 respectively include threaded housing portions404 and 406 that have external threads 408 and 410 for threadingthreaded housing portions 404 and 406 into mating threads provided in aconventional bottom bracket of a bicycle frame. These threaded portions404 and 406 provide an arrangement for connecting crank assembly 100 tothe bicycle frame.

In the embodiment shown, bearing housing arrangements 400 and 402 areconfigured to house needle bearings, (not shown in the figures).Therefore, threaded housing portions 404 and 406 also include needlebearing surfaces as indicated by surface 412 of threaded housing portion404. Bearing housing arrangements 400 and 402 also include removableneedle bearing races 414 and 416. These removable bearing races 414 and416 are pressed onto associated spindle portions 108 and 114.

As illustrated best in FIGS. 2 and 3, bearing housing arrangement 400also includes a thrust bearing 418, a thrust bearing spacer 420, athrust bearing seal 422, and a threaded bearing housing retaining ring424. Thrust bearing housing retaining ring 424 threads onto threadedbearing housing portion 404 to retain the outside diameter, or fixedportion, of thrust bearing 418 in its proper position. This axiallylocates thrust bearing 418 in its proper location in reference to thebicycle frame. The proper positioning of the rotating portion of crankassembly 100 is then achieved as one side of the inside diameter, orrotating portion, of thrust bearing 418 is positioned against spacer 420which is positioned against a thrust bearing shoulder 426 on spindleportion 108.

As illustrated in FIGS. 13 and 14, removable bearing race 414 includes ashoulder 430 and a flange 431. Also spindle portion 108 includes ashoulder 432 and spindle portion 114 includes a shoulder 434. The sideopposite retaining ring 424 of the rotating portion of thrust bearing418 is positioned against a flange 431 of removable bearing race 414.Shoulder 430 of removable bearing race 414 fixes removable bearing race414 in its axial position along spindle rotational axis 106 in itsproper position relative to spindle portions 108 and 114, as it isclamped between shoulder 432 of spindle portion 108 and shoulder 434 ofspindle portion 114.

Spindle portion 108 further includes an additional shoulder 436. Seal422 is then positioned between shoulder 436 of spindle portion 108 andbearing spacer 420 to prevent the entry of dirt and other contaminantsinto thrust bearing 418 or the needle bearings. This thrust bearingconfiguration prevents movement of the spindle arrangement axially alongspindle rotational axis 106 when the spindle arrangement is connected tothe bottom bracket of a bicycle frame.

The bearing housing arrangements described above allow for much easierremoval and disassembly of the spindle bearings compared to conventionalspindle bearing arrangements. This encourages proper maintenance ofthese components. Also, by providing bearing races 414 and 416 asseparate press fit pieces rather than integral parts of spindle portions108 and 114, these bearing races may be easily replaced without havingto discard the spindle portions.

Most BMX bicycle frames use bearing cups that press fit into the bottombracket shell of the bicycle frame as opposed to threading in to thebottom bracket as described above. This press fit bearing configurationis not very suitable for a conventional needle bearing because thehousing of a typical needle bearing is relatively flimsy. Therefore, thedistortion caused by the dramatic press fit (which can vary betweendifferent BMX frames) could place a distorted load on the needlebearing. This press fit configuration also discourages proper care andor replacing of the needle bearings since they would be fairly difficultto remove once installed. To overcome this problem, the presentinvention provides a splined bearing cartridge assembly that isolatesthe press fit portion of the bearing arrangement from the bearings. Aswill be described in more detail hereinafter, this is accomplished byplacing the bearings in a removable cartridge.

Referring now to FIGS. 13 and 14, a splined bearing cartridge system500, designed in accordance with the invention, will be described. Inthe embodiment shown, splined bearing cartridge 500 includes two bearingrings 502 and 504 that are designed to be press fit into a bottombracket of a bicycle frame such as a BMX bicycle frame. Splinedcartridge system 500 also includes a bearing cartridge 506 and a lockring 508. In this embodiment, bearing ring 502 has a spline shape 510formed into an interior portion of bearing ring 502. Bearing cartridge506 has a mating spine shape 512 that is designed to mate with splineshape 510 of bearing ring 502.

As illustrated in FIGS. 13 and 14, splined shape 512 of bearingcartridge 506 is mated with spline shape 510 of bearing ring 502 suchthat bearing cartridge 506 extends longitudinally along a spindlerotational axis 514 when assembly 500 inserted within a bottom bracketof a bicycle frame. The press fit of bearing ring 502 and the splineshapes of bearing cartridge 506 and bearing ring 502 prevent thecartridge from rotating independently of the bottom bracket of thebicycle frame.

In the embodiment being described, bearing cartridge 506 has a threadedportion 516 at the end opposite spline shape 512. Lock ring 508 isconfigured to thread onto threaded portion 516 of bearing cartridge 506so that it retains spline shape 512 of bearing cartridge 506 engagedwith spline shape 510 of bearing ring 502. This cartridge arrangementallows for easy removal of the bearings from the bottom bracket formaintenance and inspection purposes. This cartridge arrangement alsoacts as a convenient sealing system that prevents water or otherunwanted elements from entering into the needle bearings.

Although bearing rings 502 and 504 have been described as being designedto be press fit into the bottom bracket of a bicycle frame, this is nota requirement. Instead, in situations in which the bottom bracket isthreaded, bearing rings 502 and 504 would include an externally threadedportion for mating with the threaded portions of the bottom bracket.

Although the above described embodiments have been described with thevarious components having particular respective orientations, it shouldbe understood that the present invention may take on a wide variety ofspecific configurations with the various components being located in awide variety of positions and mutual orientations and still remainwithin the scope of the present invention. The present invention wouldequally apply to these various configurations. Therefore, the presentexamples are to be considered as illustrative and not restrictive, andthe invention is not to be limited to the details given herein, but maybe modified within the scope of the appended claims.

What is claimed is:
 1. A variable length crank arm arrangement for useon a bicycle frame, the variable length crank arm arrangementcomprising: a spindle having a spindle bearing surface for mounting thespindle to the bicycle frame such that the spindle is free to rotateabout a spindle rotational axis; a fixed crank arm having a longitudinalaxis extending perpendicular to the spindle rotational axis, the fixedcrank arm being fixed to the spindle for rotation with the spindle aboutthe spindle rotational axis; a floating crank arm having a longitudinalaxis, the floating crank arm being slidably connected to the fixed crankarm to allow the floating crank arm to move in a linear motion along thelongitudinal axis of the fixed crank arm while maintaining a commonlongitudinal axis with the fixed crank arm; a control bracket fixed tothe bicycle frame, the control bracket including a rotational controlbearing surface that defines a control rotational axis that is parallelwith, but spaced apart from, the spindle rotational axis, the controlbearing surface having a control bearing radius with the control bearingsurface being positioned such that the spindle rotational axis fallswithin the control bearing radius when viewed in a plane perpendicularto the spindle rotational axis; and a control arm attached to thecontrol bracket for rotation about the control axis along the controlbearing surface, the control arm being rotatably attached to thefloating crank arm such that the longitudinal axis of the floating crankarm is able to remain perpendicular to the spindle rotational axis andsuch that, as the floating crank arm is rotated about the controlrotational axis, the floating crank arm causes the control arm to rotateabout the control rotational axis and causes the fixed crank arm torotate about the spindle rotational axis thereby causing the floatingcrank arm to move back and forth along the longitudinal axis of thefixed crank arm relative to the spindle rotational axis with the overalllength of the combination of the fixed crank arm and the floating crankarm along their common longitudinal axis varying by a distance equal totwice the spacing between the control rotational axis and the spindlerotational axis.
 2. A variable length crank arm arrangement as set forthin claim 1 wherein the control rotational axis is spaced apart from thespindle rotational axis by a distance in a range of about ½″ to ⅞″ withthe control rotational axis being located above, relative to the groundwhen the bicycle frame is in the upright position, and in front of thespindle rotational axis such that the overall length of the combinationof the fixed crank arm and the floating crank arm is greatest during thedownward stroke of the crank arm arrangement as the bicycle is beingridden.
 3. A variable length crank arm arrangement as set forth in claim1 wherein the control bracket is a separate piece that is attached tothe bicycle frame.
 4. A variable length crank arm arrangement as setforth in claim 1 wherein the control bracket is provided as part of thebicycle frame.